Thermosetting coating polymers have commonly involved cross-linking polymers such as epoxy polymers, or polyester polymers having active hydrogens reactive with polyisocyanates. Polyisocyanates are toxic, water sensitive and often inconveniently require prepolymers which increase costs. Epoxy systems also are sensitive to moisture and may be toxic.
Because of their inherent scientific interest and their many actual and potential commercial applications, acetylene and non-polymeric compounds containing acetylenic groups have been extensively studied. Many reports have focused on the reactivity of acetylene. The carbon-carbon triple bonds are known to react with alcohols, acids, amines and other organic compounds with mobile hydrogen atoms under certain conditions (catalyst, temperature, pressure) to form the corresponding vinyl derivatives. This reaction is known as vinylation. These types of reactions are limited in that they only occur when carried out in an appropriate medium in the presence of a catalyst. Hennion et al., A Proposed Mechanism for Mercury Catalysis in Acetylene Addition Reactions, 1 J. Org. Chem. 159 (1936); Rutledge, T. F., Acetylenes and Allenes, Reinhold Book Corp., New York, 283 (1969). Further, while acetylene is known to react with primary and secondary aliphatic amines, this reaction also requires specific conditions and the presence of a catalyst. Kruse et al. Ethylidenimies by the Reaction of Acetylene with Primary Aliphatic Amines, 83 J. Am. Chem. Soc. 213 (1961); Kruse et al. N,N,-Dialkyl-1,1-dimethyl-2-butynylamines by the Reaction of Propyne with Secondary Aliphatic Amines, 83 J. Am. Chem. Soc. 213 (1961).
Other studies involving non-polymeric acetylenic compounds have been conducted to determine the effects of substitution on the reactivity of acetylenic groups. For example, Bowden et al. describes the addition reaction of a substituted acetylenic ketone according to the following reaction: EQU RCOC.tbd.CH+HX.fwdarw.RCOCH.dbd.CHX
where the HX group included ammonia and amine, sulfonic acids, ethylthiol and thiophenol, alcohol and phenol, halogens, hydrogen bromide, and water. Bowden et al. Researches on Acetylenic Compounds. Part VIII. Miscellaneous Addition Reactions of Ethynyl Ketones, J. Am. Chem. Soc. 945 (1946). Further, the reactivity of primary and secondary amines to acetylenes activated by the groups PhCO--, PhCH.sub.2 N(Me)CO--, MeOCO--, PhCH.sub.2 SO--, and PhCH.sub.2 SO.sub.2 -- (wherein Ph is phenyl and Me is methyl) has been described. McMullen et al. Elimination-Addition. Part VIII. Structures of Acetylene-Amine Adducts, (B) J. Chem. Soc. 1217 (1966).
While these references describe acetylenic and substituted acetylenic compounds, the references do not even suggest the use of these compounds in connection with the preparation of thermosetting polymers, or that acetylenic compounds have desirable reactivity to advantageously provide polymers and polymeric vehicles with properties which are desirable for coatings.
Acetylene based polymers are known. For example, Dirlikov has described the development of acetylene-terminated resins (ATRs) for use as hydrophobic thermosetting material. Dirlikov, Propargyl-terminated Resins--A Hydrophobic Substitute for Epoxy Resins, 2(1) High Performance Polymers 67 (1990). These ATRs are based on propargyl derivatives of bisphenols and phenolformaldehyde resins. These polymers, however, required considerable curing at high temperatures such as 208.degree. C. for 4 hours and 260.degree. C. for 6 hours.
An object of this invention is to provide a fast curing polymeric vehicle which will cure into a coating binder which is hard, has good impact resistance and is resistant of acidic and basic environments.
Another object of this invention is to provide a polymeric vehicle which is water insensitive and has a reduced toxicity over thermosetting polymeric vehicles which include isocyanates or epoxies.
Yet another object of this invention is to provide a fast curing polymeric vehicle which will cure into a coating binder at room temperature without catalysts.
Further objects and advantages of the invention will be found by reference to the following description.